If you want your page to be the same size in px all the time, use fixed widths and heights, but it will create scrollbars if the viewport resolution isn't big enough or show space all round if the resolution is larger. If you use position: absolute for each div you can position it so that it will always be in the same position from the top left corner, but as I say, in a small resolution you will get scrollbars.
If you want your page to look the same in any viewport resolution, say always having a 50px margin all round top, bottom and sides, then the page itself has to have flexible width and height. You can achieve this by not stating any widths and heights in divs, but the problem is that everything tends to get squashed together in small viewport resolutions or look very spaced out in larger resolutions.
You can avoid some problems by using min-width and max-width but these properties are not operated by IE6. You can also avoid some problems by using overflow: scroll and a height for divs so that they don't get squashed vertically causing the text to overflow outside the div or just get cut off. The flexible method needs a lot of practice and only works well with a very simple page with not much on it.
Code downloaded to my PC will be deleted in due course.
WIN7; IE9, Firefox, Opera, Chrome and Safari for Windows; screen resolution usually 1366*768.
Also IE6 on W98 with 800*600 and IE8 on Vista 1440*900.